还有一个参数没有传递，其中包括WC\\u Email对象($object 实际上是电子邮件对象的指示器；对于“-”客户、产品或电子邮件）。

传递的最后一个参数应允许您访问WC_Email 确定收件人，从而确定用户（如果您将其附加到某些用户信息（如电子邮件或用户ID）中，则应提供必要的信息，以确定正确的文件）。

尽管如此，这个答案中的一些是推测性的，因为我无法测试您的特定用例。但是如果您查看了适当的过滤器（例如includes/emails/class-wc-emails.php），那么您应该能够找出可用的方法。

我首先要探讨一下：

add_filter( \'woocommerce_email_attachments\', \'my_attachments\', 10, 4 );
function my_attachments( $attachments , $id, $object, $wc_email ) {

    // Start by checking if this is an email to the customer.    
    if ( $wc_email->is_customer_email() ) {

        // Get the recipient
        $recipient = $wc_email->get_recipient();

        /*
         * Assuming the recipient is a single email address, you can use 
         * this to figure out the info to get the attachment (i.e. your 
         * "randomName" value, which presumably has to tie out to the 
         * user somehow). IF that\'s based on the customer\'s email address,
         * then you can check $recipient directly. If it\'s the user ID,
         * then use get_user_by( \'email\', $recipient ) to get the user
         * object for the user.
         */

        $attachment_path = get_stylesheet_directory() . \'/attachments/\' . \'<randomName>.pdf\'; //How do I make the filename known here
        $attachments[] = $attachment_path;
    
    }
    return $attachments;
}